Import warning changes and people import metadata validation
Changes to metadata check for people import
Enable pre-caching mustache templates from extensions

* Previously, including them would change the path/name used in
  GGRC.Templates; now it checks for 'assets/mustache' in the path and
  removes it.
Add mustaches in ggrc_basic_permissions to GGRC.Templates
Fix import indexing issues

* In some cases, objects can exist in both `session.new` and
  `session.dirty`, so ensure we don't try to create duplicate index
  records.
lock icons appear in all program lists now
Fixed tooltips sometimes disappearing in modals
Added alphabetical sorting to People/Roles/Authorizations widgets on the admin dashboard
Refactored tree view to use instance's constructor->tree_view_options->show_view when not provided in the child_options for a sub-level; also added a new mapping for sections/objectives/controls, related_and_able_objects, to replace the former 4-5 smushed together subtrees
event listing fix
events list unmapped and deleted details
Extract context-query-filter code into `ggrc.rbac`

* Make consistent application of context filters easier
Use `session._permissions_loaded` to avoid duplicate query

* Previously, UserRole query was being executed many times per request
Added iframe sandboxing to prevent preview popovers from forcing a redirect
Merge pull request #394 from reciprocity/feature/reference_tooltip

Added iframe sandboxing to prevent iframes from redirecting
`Cache` already stores sets, so no need to convert them
Merge pull request #373 from reciprocity/feature/import_work_57098872

Import changes (network_zone related) and people import type checks
Merge pull request #388 from reciprocity/feature/private-icons-update

lock icons appear in all program lists now
Merge pull request #377 from reciprocity/feature/assets-cleanup

Fix mustache pre-caching for extensions
Added client and server permission enforcement for search counts